Welcome to ReefCentral.
Because of the sheer size of our forum, we've been forced to limit selling and trading to members who've met a couple of criteria. (If you're seeing this message, you haven't met them yet.) Please take a moment to acquaint yourself with our selling/trading rules to help make your stay a long and rewarding one.
Selling and trading on ReefCentral.

I just realized I've had mine for almost 10 years. Is there anything to look for when they fail or do they just let go? whats' the lifespan of silicon? It doesn't look like there's much silicon on the inside of the tank anymore. Maybe from years of cleaning.

If it is filled and maintaied- indefinatly. I have tanks I care for that were started in the
60s- metalframe tanks even. I have a ten gallon I got in 70 that is still fine, and has been wet and dry dozens of times. Likely the older the tank- the likely stronger the build- at least pre late 80s. Silicone would have to be seen to be judged- and that can happen to a new tank with a razor scraper and a few beers.

A long, long time... My dad had a freshwater tank for 25 years. My reef has been setup for 16 years. It is as good as new except some annoying scratches that accumulate over time. No where near as bad as an acrylic tank but, they can't easily be buffed out. This is the reason/excuse for me starting to look to an upgrade.

__________________
Reef tanks since 1987.
Current tank: 75g SPS dominated reef tank set up in 1996

if the tank is well glued, I think it will last another 10 year no problem.

__________________
Louis

I do not speak English well , please kindly give your patience to my wordy posts try to understand my words ... if there is anything wrong in my words , do not take offence because what you see may be not my true meanings.

I was just wondering this same thing today as my current reef is being revived. It's a 55 gal I got in middle school 30 years ago it's gone through 1 stand about 15 years ago. I'm trying to decide if I should replace it before I go any further. It's never been moved except once to replace the stand. It's been salt for 25 years and fresh for 5 before that. It's been in constant use since the day I bought it. Any suggestions?
If I upgrade I only have room for no more than 50 inches long and 16 to 18 wide. Height luckily isn't an issue.

I was comparing experiences a few years ago with a friend of mine who has managed a pet shop for over 38 years and we were guessing about a 10% failure rate at the 20 year mark with glass. They have one 200 display tank and a several 55s that were there when she started working there. But I have seen reputable tanks fail long before then. And like Srynx said the silicone would have to be seen to be judged. Certainly new air bubbles or changes in color would be reasons for concern. Algae working it's way into the joints between the glass would be keeping me up at night. Ironically, some of the cheaper tanks where the plastic trim around the top and bottom is used as a jig to hold the glass in place may hold up better as the plastic frame has to fail as well as the silicone joint to see a catastrophic spill.